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Engine Coolant Breakdown?

Discussion in 'Motors' started by OldKitMan, 24 Feb 2021.

  1. OldKitMan


    Joined: 18 Apr 2020

    Posts: 346

    Hi, car is at the garage as when I was checking the screenwash I noticed the expansion tank was a bit yucky, colour of the coolant seems to be less transparent and there is a load of gunk on the side of the expansion tank.

    Garage claims that coolant can break down and cause this and think a flush is required and a new expansion tank.

    However, this expansion tank was replaced by the same dealer 2 or 3 years ago (need to find the receipt) and coolant would have been changed as part of that.

    Looking at the gunky stuff I'm wondering if it's oil in the expansion tank - oil cooler seems to be a known issue on this car (insignia 1.8). Oil levels are fine and no mayo on the oil cap so looks like it could be oil mixing with the coolant.

    If coolant was to break down, which I've never seen, would it look like this?

  2. Kenai


    Joined: 5 Apr 2009

    Posts: 22,073

    I wouldn't assume a swapped expansion tank means a coolant change unless a coolant change was explicitly part of the work - it's the highest part of the system and is easy enough to suck out the coolant in the tank to change it over and then top it back up without changing the fluid in the entire loop.
  3. OldKitMan


    Joined: 18 Apr 2020

    Posts: 346

    Cheers, I'm 90% sure that I paid for coolant as well as the new expansion tank but the receipt is in the car which is at the dealers. I'll phone them up as the gunk is more than capable of being flushed out the expansion tank so I don't think a new expansion tank is required.

    My main worry is that there is a problem with the oil cooler, or even head gasket (less likely) and not fixing the problem runs a risk of the engine overheating and a much bigger job.
  4. watercooledman

    Perma Banned

    Joined: 12 Jan 2021

    Posts: 1,728

    insignia 1.8 that will be the head gasket going.
  5. OldKitMan


    Joined: 18 Apr 2020

    Posts: 346

    Garage are unable to tell me why there is gunk in the expansion tank, just that it needs flushed and a new coolant bottle. I've mentioned I'm concerned it might be a head gasket or oil cooler failure but they don't seem very interested in checking that.

    Waiting on someone calling me back. I'd assume there are relatively straightforward tests a dealer can do to check for gases and similar in the coolant system.
  6. pugheaven


    Joined: 22 Apr 2008

    Posts: 3,599

    Location: Bryn Celyn Wales

    I've never had a car that's had the coolent "break down" like that, so I have to admit, I'm dubious buying their explanation "coolant breaks down". That's looksd to me like it's being mixed with something there somewhere in the loop. Can you see around head gasket or you been losing oil?

    That gunk looks like the crud you'd get on dipsticks etc when water vapour or water gets mixed with oil... however, I'm certainly no expert, but I wouldn't be paying to replace coolent tank (at all) and coolent and flush it through until I know whats' causing it...
  7. OldKitMan


    Joined: 18 Apr 2020

    Posts: 346

    Spoke to service manager, he says it's just an advisory so I'm going to cough up the £25 or so for them to have looked at it and leave it at that. I'll have the documentation showing that as well and I'll just keep an eye on it.

    It's got a lifetime warranty with Vauxhall so if it was HGF or oil cooler that would be covered.

    They wanted £140 to flush the system entirely (new expansion tank not included in that) so I've decided to leave it. I'll take it to my local garage where my car goes and see what they say I think.

    Oil level looks fine and looks clean as well.
  8. Thebug

    Wise Guy

    Joined: 17 Feb 2007

    Posts: 1,926

    Location: Walsall

    Thats nothing to worry about, i get that too at the moment with short journeys during lockdown and colder temps means the engine doesn't get up to temp fully, i also asked at the dealers and they said they see it a lot this time of year and its nothing to worry about as long as its not loosing coolant
  9. jsmoke


    Joined: 17 Jun 2012

    Posts: 10,831

    G11 doesn't mix well with G11, G11+ etc so maybe that's what happened.